A weekly roundup of public health news
Most Americans carry cocktail of PFAS chemicals
Nearly all Americans carry a mixture of “forever chemicals” within their bodies, new research suggests.
The April 24 study, published in the Journal of Occupational and Environmental Hygiene, examined blood and plasma samples from more than 10,000 people. It found at least one type of per- and polyfluoroalkyl substance in 98.8% of samples, and multiple kinds in 98.5%.
Researchers identified dozens of different chemical combinations. The most common mixture contained perfluorohexane sulfonic acid, perfluorooctanoic acid, perfluorooctane sulfonic acid, perfluorononanoic acid and perfluoroheptane sulfonic acid. That combination of PFHxS, PFOA, PFOS, PFNA and PFHpS appeared in about 26% of samples tested.
Those five types of PFAS are among the most widely used and environmentally persistent compounds — particularly PFOA and PFOS, which were used for decades in products such as nonstick cookware, stain-resistant fabrics and firefighting foam. Because most PFAS chemicals don’t break down, they can build up in the environment and in the human body.
Previous research has linked PFAS exposure to cancers, developmental and reproductive issues, high cholesterol and hormone disruption.
Current approaches to PFAS testing and regulation often focus on individual compounds, researchers said. In 2024, the Environmental Protection Agency established PFAS drinking water standards that took combined exposures into account, but the Trump administration put the brakes on those rules.
Climate harms may hit outdoor workers harder
Many outdoor workers in the U.S. are at high risk of harm from climate hazards, but they’re often less able to protect themselves, a new study in Health Affairs says.
Published May 4, the research found that millions of people who work outside face increasing exposure to extreme heat, wildfire smoke and poor air quality, while also being more likely to lack health insurance, paid sick leave and other workplace supports.
Researchers estimated that outdoor workers made up nearly 22% of the U.S. workforce in 2023, and many lived in places with high exposure to climate-related hazards. About 17% lived in counties with the nation’s highest rates of unhealthy air quality days, while nearly one-third lived in counties with the highest levels of wildfire and heat wave exposure.
Outdoor workers also faced more economic and workplace disadvantages than indoor workers, the study found. About 16% of outdoor workers were uninsured, compared with about 8% of indoor workers. Outdoor workers were also more likely to be self-employed and were less likely to have employer-sponsored health insurance or paid sick leave. Only about 55% had access to paid sick leave, compared with more than 70% of indoor workers, researchers reported.
Workplace injuries were more common among outdoor workers as well. Nearly 3% reported being injured on the job within the previous three months, compared with about 1% of indoor workers, according to the study. Researchers said low workplace protections may leave outdoor workers with fewer options to avoid dangerous conditions or recover from illness and injury.
Outdoor jobs were more common among Hispanic workers, lower-income workers and people with less formal education. Outdoor work was concentrated in the South and West, regions increasingly affected by extreme heat and wildfire smoke, researchers noted.
Extreme heat and wildfire smoke can raise risks for heat exhaustion, injuries, respiratory illness and cardiovascular problems, especially for people doing physically demanding jobs outdoors.
The Occupational Safety and Health Administration proposed a national heat standard in August 2024 that would require employers to create safety plans and provide water, shade and paid rest breaks when temperatures rise above certain levels. Work on the standard was suspended by the Trump administration last year, however.
Polluted air linked to dementia, memory decline
Everyday exposure to air pollution may harm the way the human brain functions and ages, new research suggests.
Long-term exposure to common air pollutants is linked to higher risks of several forms of dementia, according to a May 14 study in JAMA Network Open. Researchers analyzed health data from more than 2 million older adults in Denmark, finding that higher exposure to fine-particle pollution, also known as PM2.5, was associated with increased risks of dementia.
The strongest associations were seen for dementia with Lewy bodies, a type of dementia with abnormal clumps of protein in the brain. Researchers found that every increase of 5 micrograms per cubic meter of PM2.5 exposure was associated with nearly four times greater risk of the disease. Nitrogen dioxide exposure was also linked to higher risks.
Fine-particle air pollution from sources such as traffic, industry and wildfire smoke are also linked to worse cognitive function, a May 13 study in Stroke found.
Researchers studied nearly 7,000 adults in Canada, finding that people living in areas with higher levels of PM2.5 and nitrogen dioxide performed worse on tests of memory, understanding and mental speed. Higher nitrogen dioxide exposure was also linked to small signs of brain damage that were visible on MRI scans.
People who want to avoid fine-particle air pollution might want to steer clear of airports, another new study suggests. Researchers measured air quality near a major international airport, finding extremely high levels of ultrafine particles during airplane takeoffs and landings, with concentrations reaching up to 300,000 particles per cubic centimeter of air. In comparison, urban areas typically measure about 5,000 to 40,000 particles per cubic centimeter, according to the study in Environmental Science & Technology.
Other recent public health news of note:
• Heat-related hospitalizations have increased across the U.S. in recent decades, with Black adults and low-income communities facing the greatest burden, a May 12 study in Annals of Internal Medicine finds. People living in low-income ZIP codes from 1998 to 2022 were more than twice as likely to be hospitalized for heat-related illness than those in wealthier areas.
• Patients hospitalized for pneumonia or chronic obstructive pulmonary disease can face worse outcomes at hospitals owned by private equity firms, according to research presented at the 2026 ATS International Conference. Researchers found pneumonia patients treated at private equity-owned hospitals were more likely to die during their stay than patients at other hospitals. COPD patients were also more likely to return to the hospital within 30 days, which can indicate a patient was prematurely discharged or had an avoidable complication.
• U.S. coal miners with black lung disease often experience challenges receiving benefits, a new Government Accountability Office report finds. The federal Black Lung Benefits Program provides income and medical coverage to miners who are unable to work because of the disease. But miners told federal investigators they faced problems such as long waits for claims to be processed and difficulty getting medical expenses covered by the mine operators who are responsible for their coverage. The May 11 report found the U.S. Labor Department does not do enough to monitor whether operators are providing coverage. In 2024, more than 7,700 miners received federal black lung benefits, with most beneficiaries age 62 or older.
The Watch is written by Michele Late, who has more than two decades of experience as a public health journalist.